1. Field of the Invention
The present invention relates generally to novel spray control methods and systems for controlling a sprayer, particularly, an agricultural sprayer.
2. Description of Related Art
Sprayers are widely used in agriculture and horticulture for applying chemicals (e.g., insecticides and fungicides) or fertilizers to crops, to protect the crops from diseases, insects, and to facilitate the growth and harvest of the crops.
Most agriculture/horticulture sprayers are designed to be mounted on or towed by a vehicle on the ground, or carried by airplanes or helicopters. These sprayers typically include one or more storage or supply vessels, a left and a right boom or other manifold systems that carry a plurality of geometrically arranged spaced nozzles along its length, a pump for pressurizing and distributing the fluid through pipes or hoses to spray nozzles, and means to control the pump, boom, and spray nozzles.
Currently, two basic categories of feedback controls are used for controlling the function of sprayers: (i) flow volume-based closed loop control system, and (ii) pressure-based closed loop control system. Flow volume-based feedback system measures the flow volume of the substance exiting the machine and feeds this signal back to a controller to control the performance of the machine. Pressure-based feedback system monitors the system pressure, calculates the flow volume using the pressure data, and feeds the information back to a controller to control the performance of the sprayer.
Each of the control systems has its strengths and weaknesses. However, the sprayers and application controllers known in the art only allow one of these control methods to be used for controlling the machines, with the exception of a small number of sprayers and application controllers that allow a second feedback system for monitoring purposes only.
In order to improve the performance of a sprayer, it is therefore desirable to provide a spray control system for controlling sprayers that allows both manual (the operator of the sprayer) or automatic (the controller) control of the spray system to select a feedback control system, or to switch back and forth between the two above-mentioned feedback control systems, based on the needs of the operation or operation conditions.